The present invention relates generally to particulate matter sensors for diesel engine exhaust systems and, more particularly, to arrangements for correcting for errors in such sensors.
Diesel engine manufacturers typically utilize a particulate matter sensor to measure particulates exiting the engine exhaust aftertreatment system. These sensors are susceptible to contaminates poisoning and causing measurement error. This kind of error may be referred to as aging or accumulated error. There is currently no method to correct for this error. As these contaminates accumulate, it becomes necessary to replace the sensor.
It is desirable to provide an arrangement and method that allows for the correction of this error and permits the useful life of these sensors to be extended.
In accordance with a first aspect of the present invention, a method for correcting for aging in particulate matter sensors for a diesel engine comprises calculating calculated particulate matter values for a modeled diesel engine exhaust system over a period of time, measuring measured test particulate matter values with a test particulate matter sensor over the period of time in a test diesel engine exhaust system, determining differences between the calculated particulate matter values and the measured test particulate matter values from the test particulate matter sensor over the period of time, and correcting measured particulate matter values in at least one other particulate matter sensor over a same period of time based on the determined differences to obtain a corrected particulate matter value.
In accordance with another aspect of the present invention, a particulate matter sensor arrangement comprises a particulate matter sensor configured to measure particulate matter values and produce measured particulate matter values, and a controller programmed to provide corrected measured particulate matter values for the measured particulate matter values based on determined differences between calculated particulate matter values calculated for a modeled diesel engine exhaust system over a period of time and measured test particulate matter values measured with a test particulate matter sensor over the period of time in a test diesel engine exhaust system.
In accordance with yet another aspect of the present invention, a vehicle comprises a diesel engine, an exhaust system downstream of the diesel engine, and a particulate matter sensor arrangement. The particulate matter sensor arrangement comprises a particulate matter sensor configured to measure particulate matter values in the exhaust system, and a controller programmed to provide corrected measured particulate matter values based on determined differences between calculated particulate matter values calculated for a modeled diesel engine exhaust system over a period of time and measured test particulate matter values measured with a test particulate matter sensor over the period of time in a test diesel engine exhaust system.